I spent yesterday, and the first part of today, forging with no issues. Now I can't get her to roar no matter how much psi I put to her. I increased/decreased air, moved the nozzle closer/further, & hooked up a full tank, but nothing works. Any ideas?

Good grief MAN how about a couple stills of it burning. A vid that takes up a couple three times my screen size waving around doesn't tell us anything useful.

We need a STILL pic of the burner's flame to evaluate the burner's flame. No? Another still across the forge opening from the side so we can see the dragon's breath is useful. 

I'm more than happy to help trouble shoot your burner but I need good pics. 

Frosty The Lucky.

From what I saw it doesn't appear that the pressure on the gauge is going through your burner.   The whistling/chirping sound is consistent with flames burning inside the burner tube.   That happens when there isn't enough pressure in the fuel stream to keep the flames at the end of the burner.  Usually at 30 psi you'd have a very hard time keeping the flame from blowing off the end of the burner unless you choked off most of the air. 

So, if I'm right you have one of a few possible issues: 1) You have a faulty regulator that isn't allowing the pressure shown on the gauge to go into the fuel supply line, 2) Your fuel line is partially plugged, 3) The orifice on your burner is way too small or is partially obstructed, or 4) the jet is aimed so far off center in your burner that it can't function correctly.   

The last one is the least likely to me since 30 psi of fuel with the right orifice size should still produce a lot of flame even if it wasn't suitable for forging.

 

After letting it cool off, it fired right up with no issues. I even managed to get a few heats in before it started sputtering.  It appears that once it gets up to heat, the whistling begins. Guess I'll attempt to clean out the nozzle.

Also, the other burner is the one I primarily used but it started putting out noticeably less flame. Might just need to replace them.

Since the burner is top mounted, once you shut the burner down the mixing tube will heat up if the forge is hot.   A hot mixing tube will promote early ignition and flames burning inside the mixing tube. 

However, you were showing 30 psi at your regulator.  Even with a hot mixing tube I would expect it to behave differently than what I saw and heard in the video.

In general burners don't just "go bad" where the performance deteriorates slowly and then they don't function.  Things can get plugged up and nozzles oxidize to the point where they have to be replaced, but there are no moving parts to wear out.   Even if they did, the orifice would become larger from wear and allow too much gas through.   That is not your problem here.

If your other burner is also experiencing a decrease in performance that suggests to me that your regulator is failing (that could happen in a more gradual way) or you got a propane canister with some material in it that is plugging up your burners.

There is one other option that is possible, or even likely.  Since you are using a small (BBQ size) propane tank, it may cool off fast enough to be a problem.  If you use the gas quickly enough, the temperature in the tank will drop to the point where it affects the pressure.  You can even freeze up the regulator in some cases.  However, you were still showing 30 psi on your gauge, which is on the output side of the regulator. That makes it unlikely for the regulator or tank freezing to be the issue *unless* the pressure drops rapidly when you turn the gas on at that point.  If it does, then that is most likely the source of your problems. Try placing the propane tank in a shallow pan of water and see if that changes things. Alternatively you can link 2 or more propane tanks together to slow the cooling process.

Good job covering all possibilities, Buzzkill. But answer number three gets my vote. As for the problem coming and going, that sounds pretty standard with a build up of wax and tar in the gas orifice. I predict that the burner will shut down completely a little further on. Sounds like he needs to poke a wire into the orifice, to see if a tar ball falls out. This is what torch tip cleaners, which are available from a local welding supplies store for a couple of bucks, is used for.

Tip cleaners don't fit & I pushed a wire from a steel brush in there to no avail. I've considered soaking them in alcohol to loosen anything that my be inside.

Maybe a stronger solvent then alcohol?

Also, it would take a very small orifice to be too small for most torch tip cleaners, which are made for oxyacetylene torches (smaller holes than other fuels) On the other hand, oxy-natural gas torches, which were once common, have very large holes. These tips were still around twenty years back in my neck of the woods.

I come from the school  of thought that says, "Check the easy things first."

To me the easy thing is to use it again until your problem starts to recur.  At that point look at the pressure showing on the gauge.  If it's lower than you set it and/or dropping, then you are nearly out of fuel or you're using gas fast enough to chill the tank. 

You can always take the burner and supply lines apart later and clean them if you need to, but if it's a simple matter of making a water bath for your propane tank .... well, you decide which is easier.

Soaked the nozzles in vinegar overnight and what a HUGE difference. I went ahead & ordered a pack of replacement nozzles too. I'm up to forging heat in less time than it took to go inside & get my phone. The way she's running now on 20 psi...pretty sure I can forge weld. Thanks so much for the tips guys. You brought me out of a mild depression.

Glad it helped.  Any time you use vinegar on metal you should make sure you neutralize it afterwards with something like baking soda.   If you don't then metals prone to corrosion will experience it in short order most of the time.

Thanks for that too.

A little late to the party and things seem to be performing now. I still have a couple thoughts. I can't help it, the voices won't stop talking to me.

The evidence to now says the jet was obstructed and a long vinegar soak appears to have unblocked it. The regulator doesn't look like one I'd use but your type work okay. I'm left with two thoughts, #1 propane residue. If you bought cheap propane say a blue rhino exchange tank or small fill tank, you could've gotten dirty propane. #2. and less likely, there could be manufacturing debris in the hose or fittings, after the regulator in the fuel circuit. Or it might be on the output side of the reg. 

A long vinegar soak would clear most waxy propane residues and could even dissolve metallic debris. I don't think it would dissolve rubber but cheap rubber . . . maybe.

Frosty The Lucky.